Some current models of mathematical cognition (Dehaene, 1992; Campbell & Clark, 1992) make strong claims about the code in which arithmetical operations are solved, basing themselves on how these operations were originally acquired or are most frequently employed. However, data on acquisition and use are often derived from anecdotic reports…

Studied schemes involved in solving two-step arithmetic word problems in (n=1824) elementary schoolchildren in Israel. Compound schemes and combinations of operations were found to affect the difficulty level of the problems. Appendix includes two versions of the test instrument. (Contains 17 references.) (MKR)